Seine fishing (or seine-haul fishing; ) is a method of
fishing
Fishing is the activity of trying to catch fish. Fish are often caught as wildlife from the natural environment, but may also be caught from stocked bodies of water such as ponds, canals, park wetlands and reservoirs. Fishing techniques ...
that employs a
surrounding net, called a seine, that hangs vertically in the water with its bottom edge held down by weights and its top edge buoyed by floats. Seine nets can be deployed from the shore as a beach seine, or from a boat.
Boats deploying seine nets are known as
seiners. Two main types of seine net are deployed from seiners: ''purse seines'' and ''Danish seines''. A seine differs from a
gillnet
Gillnetting is a fishing method that uses gillnets: vertical panels of netting that hang from a line with regularly spaced floaters that hold the line on the surface of the water. The floats are sometimes called "corks" and the line with corks is ...
, in that a seine encloses fish, where a gillnet directly snares fish.
Etymology
The word ''seine'' has its origins in the Old English ''segne'', which entered the language via Latin ''sagena'', from the original Greek σαγήνη ''sagēnē'' (a drag-net).
History
Seines have been used widely in the past, including by
Stone Age societies. For example, the
Māori used large canoes to deploy seine nets which could be over a kilometer long. The nets were woven from green flax, with stone weights and light wood or gourd floats, and could require hundreds of men to haul.
Native Americans on the
Columbia River wove seine nets from spruce root fibers or wild grass, again using stones as weights. For floats they used sticks made of cedar which moved in a way which frightened the fish and helped keep them together.
[Smith, Courtland ]
Seine fishing
''Oregon Encyclopedia''. Retrieved 23 March 2012.
Seine nets are also well documented in
ancient cultures in the Mediterranean region. They appear in
Egyptian tomb paintings from 3000 BC. In ancient Roman literature, the poet
Ovid
Pūblius Ovidius Nāsō (; 20 March 43 BC – 17/18 AD), known in English as Ovid ( ), was a Roman poet who lived during the reign of Augustus. He was a contemporary of the older Virgil and Horace, with whom he is often ranked as one of the ...
makes many references to seine nets, including the use of cork
floats and lead weights.
[Johnson WM and Lavigne DM (1999]
''Monk Seals in Antiquity''
Fisheries, pp. 48–54. Netherlands Commission for International Nature Protection.
Purse seine
A common type of seine is a purse seine, named such because along the bottom are a number of rings. A line (referred to as a purse-line) passes through all the rings, and when pulled, draws the rings close to one another, preventing the fish from "sounding", or swimming down to escape the net. This operation is similar to a traditional style purse, which has a drawstring.
The purse seine is a preferred technique for capturing fish species which
school
A school is an educational institution designed to provide learning spaces and learning environments for the teaching of students under the direction of teachers. Most countries have systems of formal education, which is sometimes compu ...
, or aggregate, close to the surface:
sardine
"Sardine" and "pilchard" are common names for various species of small, oily forage fish in the herring family Clupeidae. The term "sardine" was first used in English during the early 15th century, a folk etymology says it comes from the ...
s,
mackerel
Mackerel is a common name applied to a number of different species of pelagic fish, mostly from the family Scombridae. They are found in both temperate and tropical seas, mostly living along the coast or offshore in the oceanic environment.
...
,
anchovies
An anchovy is a small, common forage fish of the family Engraulidae. Most species are found in marine waters, but several will enter brackish water, and some in South America are restricted to fresh water.
More than 140 species are placed in 1 ...
,
herring
Herring are forage fish, mostly belonging to the family of Clupeidae.
Herring often move in large schools around fishing banks and near the coast, found particularly in shallow, temperate waters of the North Pacific and North Atlantic Ocea ...
, and certain species of
tuna
A tuna is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae ( mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bullet tuna (max le ...
(schooling); and
salmon
Salmon () is the common name
In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of ...
soon before they swim up rivers and streams to spawn (aggregation). Boats equipped with purse seines are called
purse seiners.
Purse seine fishing can result in smaller amounts of by-catch (unintentionally caught fish), especially when used to catch large species of fish (like herring or mackerel) that
shoal
In oceanography, geomorphology, and geoscience, a shoal is a natural submerged ridge, bank, or bar that consists of, or is covered by, sand or other unconsolidated material and rises from the bed of a body of water to near the surface. It ...
tightly together.
[Purse-seining: when fishing methods go bad](_blank)
Greenpeace, 18 May 2010 When used to catch fish that shoal together with other species, or when used in parallel with
fish aggregating devices, the percentage of by-catch greatly increases.
Use of purse seines is regulated by many countries; in
Sri Lanka
Sri Lanka (, ; si, ශ්රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...
, for example, using this type of net within of the shore is illegal. However, they can be used in the deep sea, after obtaining permission from authorities. Purse seine fishing can have negative impacts on fish stocks because it can involve the bycatch of non-target species and it can put too much pressure on fish stocks.
Power block
The power block is a mechanized pulley used on some seiners to haul in the nets. According to the UN
Food and Agriculture Organization
The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...
, no single invention has contributed more to the effectiveness of purse seine net hauling than the power block.
[ FAObr>Fishing Equipment: Power block]
/ref>
The Puretic power block line was introduced in the 1950s and was the key factor in the mechanization of purse seining. The combination of these blocks with advances in fluid hydraulics and the new large synthetic nets changed the character of purse seine fishing. The original Puretic power block was driven by an endless rope from the warping head of a winch. Nowadays, power blocks are usually driven by hydraulic pumps powered by the main or auxiliary engine. Their rpm, pull and direction can be controlled remotely.
A minimum of three people are required for power block seining; the skipper, skiff operator, and corkline stacker. In many operations a fourth person stacks the leadline, and often a fifth person stacks the web.
Drum
In certain parts of the western United States as well as Canada, specifically on the coast of British Columbia, drum seining is a method of seine fishing which was adopted in the late 1950s and is used exclusively in that region.
The drum seine uses a horizontally mounted drum to haul and store the net instead of a power block. The net is pulled in over a roller, which spans the stern, and then passes through a spooling gear with upright rollers. The spooling gear is moved from side to side across the stern which allows the net to be guided and wound tightly on the drum.
There are several advantages to the drum seine over the power block. The net can be hauled very quickly - at more than twice the speed of using a power block, the net does not require overhead handling, and the process is therefore safer. The most important advantage is that the drum system can be operated with fewer deckhands. However, it is illegal to use a seine drum in the state of Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S ...
.
Danish seine
A Danish seine, also occasionally called an anchor seine, consists of a conical net with two long wings with a bag where the fish collect. Drag lines extend from the wings, and are long so they can surround an area.
A Danish seine is similar to a small trawl
Trawling is a method of fishing that involves pulling a fishing net through the water behind one or more boats. The net used for trawling is called a trawl. This principle requires netting bags which are towed through water to catch different spe ...
net, but the wire warps are much longer and there are no otter boards. The seine boat drags the warps and the net in a circle around the fish. The motion of the warps herds the fish into the central net.
Danish seiner vessels are usually larger than purse seiners, though they are often accompanied by a smaller vessel. The drag lines are often stored on drums or coiled onto the deck by a coiling machine. A brightly coloured buoy, anchored as a "marker", serves as a fixed point when hauling the seine. A power block, usually mounted on a boom or a slewing deck crane, hauls the seine net.
Danish seining works best on demersal fish
Demersal fish, also known as groundfish, live and feed on or near the bottom of seas or lakes (the demersal zone).Walrond Carl . "Coastal fish - Fish of the open sea floor"Te Ara - the Encyclopedia of New Zealand. Updated 2 March 2009 They o ...
which are either
scattered on or close to the bottom of the sea, or are aggregated ( schooling). They are used when there are flat but rough seabeds which are not trawlable. It is especially useful in northern regions, but not much in tropical to sub-tropical areas.
The net is deployed, with one end attached to an anchored dan (marker) buoy, by the main vessel, the seiner
A fishing vessel is a boat or ship used to catch fish in the sea, or on a lake or river. Many different kinds of vessels are used in commercial, artisanal and recreational fishing.
The total number of fishing vessels in the world in 2016 was es ...
, or by a smaller auxiliary boat. A drag line is paid out, followed by a net wing. As the seiner sweeps in a big circle returning to the buoy, the deployment continues with the seine bag and the remaining wing, finishing with the remaining drag line. In this way a large area can be surrounded. Next the drag lines are hauled in using rope-coiling machines until the catch bag can be secured.
The seine netting method developed in Denmark. Scottish seining ("fly dragging") was a later modification. The original procedure is much the same as fly dragging except for the use of an anchored marker buoy when hauling, and closing the net and warps and net by winch.
Other images
See also
* Seiners
Notes
References
*
* Gabriel O., von Brandt A., Lange K., Dahm E. and Wendt T. (2005) ''Fish catching methods of the world''
''Seining in fresh and sea water''
Wiley-Blackwell, Page 431–448.
Seine nets
Fishing Gear Types. FAO, Rome. Retrieved 13 March 2012.
Beach seines
Fishing Gear Types. FAO, Rome. Retrieved 13 March 2012.
Boat seines
Fishing Gear Types. FAO, Rome. Retrieved 13 March 2012.
Two boat purse seining
Fishing Techniques. FAO, Rome. Retrieved 13 March 2012.
Purse seines
Fishing Gear Types. FAO, Rome. Retrieved 13 March 2012.
External links
WorldFishingToday - Fishing vessels photos and data
Video: Purse Seine Fishing
Video: Purse Seine Delivery - Prince William Sound, Alaska
Video: Purse Seiner at Work
Video: Traditional purse seining in the Bali Strait, Indonesia
* ttps://web.archive.org/web/20090430153417/http://www.fisheriesmanagement.co.uk/seine_netting.htm Seine Netting
Purse Seining
''Seafood Watch'', Fishing Methods Fact Card. Retrieved 23 January 2012.
* Thomson, David: Pair trawling and pair seining. The technology of two-boat fishing. Farnham: Fishing News Books, 1978
* Thomson, David B.: Seine fishing. Bottom fishing with rope warps and wing trawls. Farnham: Fishing News Books, 1981
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Fishing industry
Fishing equipment
Fishing techniques and methods
Fishing nets